From: Greg Banks <gnb@sgi.com>
Subject: Re: [PATCH] exponential backoff for blocked LOCK call polling
Date: Tue, 9 Nov 2004 09:54:11 +1100
Message-ID: <20041108225411.GA29190@sgi.com>
References: <1098786131.21421.484.camel@hole.melbourne.sgi.com> <Pine.LNX.4.60.0411081021570.16292@harp.ngdc.noaa.gov>
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Cc: Greg Banks <gnb@melbourne.sgi.com>,
        Trond Myklebust <trond.myklebust@fys.uio.no>,
        Linux NFS Mailing List <nfs@lists.sourceforge.net>
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To: "Ara.T.Howard" <Ara.T.Howard@noaa.gov>
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On Mon, Nov 08, 2004 at 10:27:19AM -0700, Ara.T.Howard wrote:
> On Tue, 26 Oct 2004, Greg Banks wrote:
> if i read your code right it looks like, once max delay is reached, it stays
> there.

Yes.

>  this will mean that a client waiting a long time has an increasingly
> significant change of being starved when a lock is under heavy contention
> doesn't it?

Not if the server has queued the lock request.  But then if the server
were correctly implemented it would probably be sending us a GRANTED
callback and we wouldn't need to poll.

>  in any case it seems like resetting the delay to min after
> reaching max (becoming impatient again) may give better performance on 
> average
> than simply staying at max.

Could do.  Do you want to do the patch?

Greg.
-- 
Greg Banks, R&D Software Engineer, SGI Australian Software Group.
I don't speak for SGI.


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